Intubation is the placement of an intubation tube of an intubation device into a lumen (i.e., trachea or esophagus) of the body of a subject in order to provide ventilation by mechanical or artificial means via the intubation tube. Intubation can be in the form of tracheal intubation, which is the placement of a tube into the trachea of a subject, as well as esophageal intubation, which is the placement of a tube into the esophagus of a subject.
Intubation is a potentially dangerous invasive procedure with many plausible errors when performed improperly. An example of an intubation error is over-inflation of a cuff, where the cuff is an inflatable bulb coupled to an exterior wall of the intubation tube and used to maintain a position of the intubation tube in the lumen. Over-inflation of the cuff can result in a patient's internal bleeding or, potentially, death. Another example of a common intubation error is the insertion of the intubation tube in the wrong lumen, potentially suffocating the patient. Even with proper training, medical caregivers cannot visually inspect which lumen the intubation tube was inserted into, and, under stress of emergency response, the medical caregiver can make an insertion error and injure the subject, sometimes fatally. FIGS. 1 and 2 illustrate the foregoing examples.
FIG. 1 illustrates a first subject 101 requiring an intubation tube to assist in the subject's breathing, e.g., due to a health problem that impairs or stops normal breathing. To aid the subject, a medical caregiver may employ an intubation device 100. The procedure for using a traditional intubation device begins by the medical caregiver's clearing the subject's mouth and airway, if needed, then inserting an intubation tube 105 of the intubation device 100 into the subject's trachea or esophagus, depending of the type of intubation device being used. During insertion, the cuff(s) 110 on the intubation tube 105 are in a deflated state. Once the intubation tube 105 is in an inserted position, the medical caregiver can stabilize a position of the intubation tube 105 by inflating the cuff(s) 110 through use of a pilot cuff 120 by a syringe filled with either air or a liquid. The pilot cuff 120 is connected to the cuff(s) 110 via tubing 125 for manual inflation of the cuff(s) 110. Once the cuff(s) 110 are inflated and have stabilized the position of the intubation tube 105, ventilation via the intubation tube through use of a ventilator 102 can begin. As mentioned above, over-inflation of the cuff(s) may result in complications, and the complications may manifest themselves as mucosal bleeding and ischemia, esophageal or tracheal bleeding, or death.
FIG. 2 illustrates a second subject 201 also requiring intubation, in which an intubation tube 205 of an intubation device 200 has been inserted into a lumen. In this example scenario, the intubation tube 205 has been inserted into the incorrect lumen 220, which can result in suffocation of the patient, as well as other complications, including death (see von Goedecke et al. (2007) Anesth Analg, 104:481-483; and ACLS: Principles and Practice. pp. 135-180. Dallas: American Heart Association, 2003) as the resuscitation provided to the patient through use of a ventilator 202 would enter the epigastrium rather than the lungs of the subject.
Current methods and devices used for confirming correct tube placement of the intubation device include: visualization of chest movement during ventilation, sound detection of auscultation of chest and epigastrium, checking for fogging of the intubation device, absence of stomach contents in the device, colorimetric end tidal CO2 detection, waveform capnography, self-inflating esophageal bulb, and pulse oximetry. Verification of cuff inflation level is generally not checked, as the maximal volume of the cuff is generally used and presumed to be accurate.
In addition to unaided visual verification, image sensor systems that employ fiber optic cameras can be used to verify cuff inflation and proper tube placement. Such image systems are not generally used because they are cost prohibitive and, in most cases, unnecessary. Moreover, medical caregivers would have to carry both intubation devices and image sensor systems whenever responding to an emergency, which would complicate or delay response time.
Unfortunately, each method by itself is neither efficient nor reliable for confirming correct tube placement. Thus, the use of multiple methods to confirm correct tube placement is currently the standard of care, which delays a medical caregiver from providing treatment to the subject, possibly leading to unintended injury to the subject.